Terahertz pulsed imaging as an analytical tool for sustained-release tablet film coating

Ho, Louise; Müller, Ronny; Gordon, Keith C.; Kleinebudde, Peter; Pepper, M.; Rades, Thomas; Shen, Yaochun; Taday, PF; Zeitler, J. Axel

doi:10.1016/j.ejpb.2008.06.023

Cited by 66 publications

(45 citation statements)

References 22 publications

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“…Inset of (d) shows schematic diagram of a layered sample, which is a plastic plate with 6-mm-thick cling film layer and 18-mm-thick polymer layer. that could be precisely quantified using TPI is about 40 mm for this specific set of tablets, which is in good agreement with previous reports [7,16]. TPI technology could not provide precise coating thickness information for tablets with weight gains of 1.8, 3.6 and 5.5 mg/cm 2 .…”

Section: Resultssupporting

confidence: 89%

“…The coating formulation used is as follows: 50% w/w polyvinyl acetate (Kollicoat s SR 30D), 6% w/w polyvinyl alcoholpolyethyleneglycol graft copolymer (Kolicoat s IR), 0.075% w/w polyoxyethylene(20) sorbitan monooleate (Polysorbate 80), 0.3% w/w glycerolmonostearate, 0.75% w/w triethylcitrate and 42.87% w/w deionised water. The tablets were randomly selected after the following amounts of the sustained-release polymer were applied: 1.8, 3.6, 5.5, 7.3, 9.1, 10.9, 12.7, 14.5 and 18.2 mg/cm 2 [16].…”

Section: Methodsmentioning

confidence: 99%

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Non-destructive quantification of pharmaceutical tablet coatings using terahertz pulsed imaging and optical coherence tomography

Zhong¹,

Shen

et al. 2011

Optics and Lasers in Engineering

124

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Optical coherence tomography (OCT) and terahertz pulsed imaging (TPI) are two powerful techniques allowing high quality cross-sectional images from within scattering media to be obtained non-destructively. In this paper, we report experimental results of using OCT and TPI for quantitatively characterizing pharmaceutical tablet coatings in the thickness range of 10–140 μm. We found that the spectral OCT system developed in-house has an axial resolution of 0.9 μm, and is capable of quantifying very thin coatings in the range of 10–60 μm. The upper limit of 60 μm within the tablet coating and core is owed to the strong scattering of OCT light, which has relatively short wavelengths in the range of 0.5–1.0 μm. On the other hand, TPI utilizes terahertz radiation that has substantially long wavelengths in the range of hundreds of microns, and thus is less prone to the scattering problem. Consequently TPI has been demonstrated to be able to quantify thicker coatings in the range of 40–140 μm and beyond. We concluded that OCT and TPI are two complementary analytical techniques for non-destructive and quantitative characterization of pharmaceutical tablet coatings

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Section: Resultssupporting

confidence: 89%

Section: Methodsmentioning

confidence: 99%

Non-destructive quantification of pharmaceutical tablet coatings using terahertz pulsed imaging and optical coherence tomography

Zhong¹,

Shen

et al. 2011

Optics and Lasers in Engineering

124

View full text Add to dashboard Cite

show abstract

“…To date, a number of studies have highlighted how this technology can be used in coating development by imaging the coating thickness distribution over the surface of solid dosage forms and correlating the findings to drug release characteristics in dissolution testing. [14][15][16][17][18][19][20] In addition to measuring coating thickness, TPI can also yield further information such as the refractive index of the tablet surface which in turn can be critical to drug release from coated tablets. 15 …”

Section: Introductionmentioning

confidence: 99%

Terahertz In-Line Sensor for Direct Coating Thickness Measurement of Individual Tablets During Film Coating in Real-Time

May

Evans

Zhong

et al. 2011

Journal of Pharmaceutical Sciences

125

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“…Ho et al have published several articles describing the application of THz imaging based on time-domain measurements (72)(73)(74). Using a commercially available THz-TDS scanning reflectance instrument (72), data were collected across the surface of the tablet, after which the data were assembled to produce a three-dimensional image that represents the coating thickness across the tablet surface (72)(73)(74).…”

Section: Imaging Analysis Of Pharmaceutical Solidsmentioning

confidence: 99%

Terahertz Time-Domain Spectroscopy of Solid Samples: Principles, Applications, and Challenges

Smith

Arnold

2011

Applied Spectroscopy Reviews

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Advances in ultrafast lasers and semiconductor technologies have facilitated access to the terahertz (THz) frequency range for spectroscopic and imaging purposes. THz time-domain spectroscopy (TDS) is commonly used to acquire spectral data having high signal-to-noise ratios (SNRs) over a broad range of THz frequencies. THz-TDS instrumentation is commercially available, thereby enabling novel applications of THz time-domain (TD) imaging and spectroscopy in a myriad of applications. This review gives a general description of the instrumentation available for collecting THz-TD data and focuses on measurements of solid samples. Measurement geometries useful forcollecting THz-TD data from solid samples are reviewed and a summary is presented of the major applications to the analysis of solid samples related to security issues, as well as samples originating from the pharmaceutical industry, dental sciences, biological samples, and polymer materials. Emphasis is also given to analytical applications in a discussion of the analytical challenges met in quantification of solid analytes by THz-TDS methods.

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Terahertz pulsed imaging as an analytical tool for sustained-release tablet film coating

Cited by 66 publications

References 22 publications

Non-destructive quantification of pharmaceutical tablet coatings using terahertz pulsed imaging and optical coherence tomography

Non-destructive quantification of pharmaceutical tablet coatings using terahertz pulsed imaging and optical coherence tomography

Terahertz In-Line Sensor for Direct Coating Thickness Measurement of Individual Tablets During Film Coating in Real-Time

Terahertz Time-Domain Spectroscopy of Solid Samples: Principles, Applications, and Challenges

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